Device and method for controlling dissemination of contents between peers having wireless communication capacities, depending on impatience reaction functions

ABSTRACT

A method is intended for controlling dissemination of content in a peer-to-peer mode between peers having wireless communication capacities. This method consists, each time a peer receives a content item it had requested and which is associated to a request counter, in creating at least one set of instructions intended for allowing replication of this content item by this peer, and in authorizing this peer to generate at most N replications of this content item for other peers it will meet and which does not possess it, where N is an integer value depending on the current value of this request counter and of an impatience reaction function which is representative of the mean time these peers are ready to wait for obtaining this content item.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of co-pending U.S. patent applicationSer. No. 12/799,876 filed on May 4, 2010, which is incorporated hereinby reference.

BACKGROUND

1. Field of the Invention

The present invention relates to content dissemination between peers ina peer-to-peer (or “P2P”) wireless environment.

One means here by “peer” a wireless communication equipment capable ofexchanging data (or symbols (i.e. blocks or packets or chunks of data))with other peers or network equipments in a P2P mode through wirelesscommunications. So, a peer may be a laptop, a smartphone, a mobile orcellular telephone, a personal digital assistant (PDA), provided that itcomprises a wireless communication interface (or any equivalent wirelesscommunication means), or a node associated to a vehicle (for instance abus or a car) or a base station that is assisting opportunistic contentdelivery in an area (such as a content “booth” (or a “throwbox”)).

Moreover, one means here by “content dissemination” the transmission ofcontent data between peers in order each of these peers had thesecontent data at its disposal or at the disposal of other peers.

More, one means here by “content” any type of set of data that can bedisseminated in a P2P mode, and notably files of information data,videos, chunks of video, pictures to share, html files, audio files andsoftware updates, and more generally any type of file, hereafter called“item”.

2. Description of the Prior Art

The number of wireless communication equipments (and notably mobiletelephones, smartphones and portable equipments), capable of displaying,storing and transmitting contents, is increasing, and the operators ofwireless communication networks are facing a main issue: how todisseminate the contents efficiently between wireless communicationequipments.

Today, most of the wireless content dissemination applications proceedto content dissemination by means of a direct transmission through acentralized infrastructure. However, this solution is both expensive forthe content provider and inefficient from a networking perspective as itleaves unused the potentially very large quantity of bandwidth which isavailable for content exchange between wireless communication equipmentswithin short range radio transmission (e.g. Bluetooth or IEEE 802.11).

Networks that leverage local connection opportunities to communicate ina delay tolerant manner can be classified into two different categories.A first category comprises networks involving nodes with scheduled orcontrolled routes and using a routing protocol to communicate criticalinformation in due time. A second category comprises networks to whichwireless communication equipments with unpredictable mobility areconnected, e.g. because their users are attending a conference or acommon event. In the latter case, no protocol can guarantee to deliver amessage within a fixed time although the performance of a peer-to-peerapplication can still be acceptable.

It is recalled that in a P2P environment, communication equipments (orpeers) meet according to a simple homogeneous and memoryless process, asif they follow uncoordinated mobility, and have a dedicated buffer (orcache memory) which can be filled with content items (or files) thatcould be requested later by other peers. The demands (or requests) fordifferent content items arise according to a stationary regime that canfollow an arbitrary popularity distribution. In contrast withtraditional fixed P2P networks, in wireless P2P networks the timeelapsed between the demand arising and the fulfillment of this demandcan be far from negligible. So, this time elapsed (or delay to fulfil arequest) plays an important role in the perception of the P2P network byusers. Indeed, in some cases it may happen that the interest for acontent item becomes obsolete before the peer has any chance to receivethis content item. Such a behavior is generally referred to as“impatience”.

SUMMARY

So the object of this invention is to provide a method and an associatedcontrol device allowing to reduce the mean time that is necessary to awireless communication equipment to obtain a chosen content item in awireless P2P environment by an appropriate allocation of content tocache memory, and notably by taking the best advantage of contactopportunities between peers under general conditions on contentpopularity and user behavior.

More precisely, the invention provides a method, intended forcontrolling dissemination of content in a peer-to-peer mode betweenpeers having wireless communication capacities, and comprising the stepsof, each time a peer receives a content item it had requested and whichis associated to a request counter (used during the search phase):

i) creating at least one set of instructions intended for allowingreplication of this content item by the considered peer, and

ii) authorizing this considered peer to generate at most N replicationsof this content item for other peers it will meet (in the future) andwhich does not yet possess it, where N is an integer value depending onthe current value (V1 _(ri)) of the request counter and of an impatiencereaction function (f_(i)) which is representative of the mean time thepeers (of the network) are ready to wait for obtaining this contentitem.

The method according to the invention may include additionalcharacteristics considered separately or combined, and notably:

N may be a power function of the type A. f_(i)(V1 _(ri))=A.V1 _(ri)^(ri) or of the type A.f_(i)(V1 _(ri))=A.V1 _(ri) ^((ri−1)/ri), forinstance, where A is a chosen normalization constant;

in step ii), each time the considered peer meets another peer which doesnot possess a content item that it is still authorized to replicate, onemay generate a replication of this content item by means of theassociated set of instructions, and this considered peer may transmitthis generated replication to the other peer;

in step ii) one may generate the replication of a content item if, andonly if, the other peer has requested this content item;

in a variant, in step (ii) one may generate automatically thereplication of a content item for the other peer even if the latter hasnot requested this content item;

when the other peer receives the replication of the content item andcomprises a cache memory for storing content items, this receivedreplication may replace the oldest content item of this cache memory ifthe latter is full;

each time a peer receives a content item, it may store this content iteminto a cache memory, and one may associate a replication counter (usedin the replication phase) to this content item, with an initial value(V2 _(ri)) equal to N, for this considered peer, and each time thisconsidered peer generates a replication of a content item (associated toa replication counter and stored into this cache memory), one maydecrement by one the value (V2 _(ri)) of this replication counter, andwhen the replication counter value (V2 _(ri)) becomes equal to 0, onemay delete this replication counter;

when a content item is no more stored into a cache memory of a peerwhile the value (V2 _(ri)) of the replication counter associated to thiscontent item is smaller than N, one may keep this replication counterwith its current value (V2 _(ri)), and if this considered peer receivesagain this content item, one may associate this replication counter withits current value (V2 _(ri)) to this received content item;

one may keep the replication counter with its current value (V2 _(ri))during a chosen period of time, and if the considered peer receivesagain a content item before the expiration of this period of time, onemay associate this replication counter with its current value (V2 _(ri))to this received content item, otherwise this replication counter isdeleted at the expiration of its associated period of time;

in step i) one may create N sets for N replications of a new contentitem, and each time a replication of this content item needs to begenerated, one may use a remaining one of these N created setsassociated to this content item.

The invention also provides a control device, intended for controllingdissemination of content in a peer-to-peer mode from an associated peerto other peers through wireless communications, and arranged, each timeits associated peer receives a content item it had requested and whichis associated to a request counter having a current value (V1 _(ri)):

for creating at least one set of instructions intended for allowingreplication of this content item by its associated peer, and

for computing an integer value N, which depends on the current value (V1_(ri)) of this request counter and of an impatience reaction function(t) which is representative of the mean time the peers (of the network)are ready to wait for obtaining this content item, in order to authorizeits associated peer to generate at most N replications of this contentitem for other peers it will meet (in the future) and which does not yetpossess it.

The control device according to the invention may include additionalcharacteristics considered separately or combined, and notably:

it may be arranged, each time its associated peer meets another peerwhich does not possess a content item, for checking if its associatedpeer is still authorized to generate a replication of the content item,and in the affirmative for authorizing such a generation by means of theassociated set of instructions;

it may be arranged, each time it authorizes its associated peer togenerate a replication of a content item (associated to a replicationcounter and stored into a cache memory), for decrementing by one thevalue (V2 _(ri)) of this replication counter, and when this replicationcounter value (V2 _(ri)) becomes equal to 0, for deleting thisreplication counter;

it may be arranged, when a content item is no more stored into a cachememory of its associated peer, while the value (V2 _(ri)) of thereplication counter associated to this content item is smaller than N,for keeping this replication counter with its current value (V2 _(ri)),and when its associated peer receives again this content item, forassociating this replication counter with its current value (V2 _(ri))to this received content item;

it may be arranged for keeping the replication counter with its currentvalue (V2 _(ri)) during a chosen period of time, and, if its associatedpeer receives again a content item before the expiration of this periodof time, for associating this replication counter with its current value(V2 _(ri)) to this received content item, otherwise for deleting thisreplication counter at the expiration of its associated period of time;

it may be arranged for creating N sets for replications of a contentitem, and, each time a replication of this content item needs to begenerated, for providing its associated peer with a remaining one ofthese N created sets associated to this content item.

The invention also provides a peer (or wireless communication equipment)capable of establishing connection(s) with other peers through wirelesscommunications and comprising a control device such as the one aboveintroduced.

BRIEF DESCRIPTION OF THE DRAWINGS

Other features and advantages of the invention will become apparent onexamining the detailed specification and the appended drawing, whereinFIG. 1 schematically and functionally illustrates four wirelesscommunication equipments (or peers) connected to a wirelesscommunication network and each comprising an example of embodiment of acontrol device according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The appended drawing may serve not only to complete the invention, butalso to contribute to its definition, if need be.

The invention aims at offering a method and an associated control deviceD allowing to control P2P dissemination of contents between peers Pj(here, j=1 to 4) connected therebetween through wireless communications.

For instance these wireless communications are established via awireless communication network WN. In the following description it willbe considered that the wireless communication network WN is an IEEE802.11 network (i.e. a WLAN (Wireless Local Area Network), for instanceof the WiFi type). But the invention is not limited to this type ofwireless communication network. Indeed, a wireless communication networkmay be also a mobile or cellular network, a Zygbee network, an UltraWide band network, an IEEE 802.15 network, or a Bluetooth network, forinstance.

Moreover, in the following description it will be considered that peersPj are mobile telephones. But the invention is not limited to this typeof wireless communication equipment. Indeed, the invention concerns anytype of wireless communication equipment comprising at least oneexecutable P2P communication application and capable of exchanging data(or symbols) with other wireless communication equipments or networkequipments in a P2P mode through wireless communications. So, a peer maybe also a laptop, a smartphone, a personal digital assistant (PDA),provided that it comprises a wireless communication interface (or anyequivalent wireless communication means), or a node associated to avehicle (for instance a bus or a car) or a base station that isassisting opportunistic content delivery in an area (such as a content“booth” (or a “throwbox”)).

More, in the following description it will be considered that thecontents to be disseminated are videos. But the invention is not limitedto this type of content. Indeed, the invention concerns any type ofcontent which can be disseminated in a P2P mode, and notably files ofinformation data, chunks of video, pictures to share, html files, audiofiles and software updates, and more generally any type of file.

As illustrated in FIG. 1, contents may be initially provided to some ofthe peers Pj, through the (wireless communication) network WN, by acontent server CS which is connected or accessible to said network WN.

The invention concerns a group of at least two peers Pj (here mobiletelephones). In the illustrated and non limiting example the groupcomprises four peers P1 to P4 (j=1 to 4). But the invention concerns anygroup comprising at least two peers capable of exchanging content datatherebetween.

As mentioned before the invention offers notably a method intended forcontrolling dissemination of content (and more precisely of contentitems CIi) in a peer-to-peer (P2P) mode between peers Pj. This methodcomprises two main steps which are implemented each time a peer Pjreceives a content item CIi it had requested before and which isassociated to a request counter RC1 _(ji).

It is important to note that each peer Pj comprises a first cache memory(or buffer) CMj in which it stores content items CIi received from otherpeers Pj′ (j′≠j) or from the content server CS, in order of arrival.When the first cache memory (or buffer) CMj is full and that its peer Pjreceives a content item, the oldest content item it contains is replacedwith this content item.

Moreover, when a peer Pj wants to obtain a content item CIi, itgenerates a dedicated request or demand containing an identifier of thisrequested content item CIi and transmits this dedicated request to oneor more other peers Pj′ (j′≠j), eventually selected. One assumes, here,that the gain of a request being fulfilled is a function of the timeelapsed since this request was expressed (or generated).

More, each time a peer Pj generates a dedicated request for a contentitem CIi, it also creates a request counter RC1 _(ji) which is dedicatedto this content item CIi and which has an initial value V1 _(ri) set tozero. Then, each is time this peer Pj meets (or contacts) an other peerPj′(j′≠j) and cannot obtain the requested content item CIi from thisother peer Pj′, it increments by one the value V1 _(ri) of this requestcounter RC1 _(ji), and when the value V1 _(ri) of this request counterRC1 _(ji) becomes equal to a chosen (maximum) value M (for instanceequal to 500 (but it may take any chosen value)) it remains at thisvalue M. In a variant, the value V1 _(ri) of the request counter RC1_(ji) may be automatically and periodically incremented by one as longas the peer Pj does not obtain the corresponding requested content itemCIi from another peer Pj′, and when the value V1 _(ri) of this requestcounter RC1 _(ji) becomes greater than a chosen value M (for instanceequal to 500) it remains at this value M. In both cases, when the peerPj obtains a requested content item CIi from another peer Pj′, itdeletes the corresponding request counter RC1 _(ji).

One may assume that contacts (or meetings) between peers Pj an Pj′ occurin continuous time and follow the statistics of a Poisson process withrate .mu. One may also assume that contacts between peers Pj an Pj′ aresymmetric (Pj contacts Pj′ whenever Pj′ contacts Pj). This assumptionmodels well a situation where peers attend a common event.

The method, according to the invention, can be implemented by controldevices D according to the invention which are respectively associatedto peers Pj, i.e. which are each dedicated to the control of contentdissemination of one associated peer Pj.

As it is schematically illustrated in FIG. 1, each (control) device Dmay be located into its associated peer Pj. But each device D could bealso an equipment or element coupled to its associated peer Pj.

So, a device D can be made of software modules, at least partly, or ofelectronic circuit(s) or hardware modules, or else of a combination ofhardware and software modules (in this case the device D comprises alsoa software interface allowing interworking between the hardware andsoftware modules).

A first main step (i) of the method consists, when a peer (for instanceP1) receives a new requested content item CIi (associated to a requestcounter RC1 _(1i)), from another peer Pj′ (j′≠1) or from the contentserver CS, in creating at least one set of instructions (or “mandate”)which is intended for allowing replication of this content item CIi bythis peer P1.

A first main step (i) can be implemented by means of the device D whichis associated to peer P1. More precisely, the device D of peer P1 isarranged, each time the latter (P1) receives a requested content itemCIi for creating at least one set of instructions (or mandate) to allowits peer P1 to generate at least one replication of this content itemCIi.

A second main step (ii) of the method consists in authorizing the peerP1 to generate at most N replications of the content item CIi for atleast N other peers Pj′ (j′≠1) it will meet in the future and which doesnot yet possess this content item CIi.

According to the invention, N is an integer value which depends on thecurrent value V1.sub.ri of the request counter RC1 _(ji) (which isassociated to the content item CIi received by peer Pj) and of animpatience reaction function f_(i) dedicated to this content item CIi.

This impatience reaction function f_(i) is a function which is known byevery peer Pj and which is representative of the mean time the peers Pjof the network WN are ready to wait for obtaining a content item CIi. Inother words an impatience reaction function f_(i) denotes the value offulfilling a request for a content item CIi after some time. So, animpatience reaction function f_(i) characterizes how the allocationdepends on popularity of contents. It can be shown that if the users aremonotonically impatient (i.e. if they receive higher gain when theirdemand is satisfied faster) then a unique optimal cache memoryallocation exists, in the sense that it satisfies user needs in the bestpossible way, accounting for their impatience. However, computing thisoptimal allocation requires to have a good estimate of the frequency ofdemands (or requests) for each content item, and it can becomputationally expensive. This invention is precisely bypassing thiscostly step, by means of a distributed adaptive mechanism which is shownto converge to this optimal point, without the need to maintain estimateof frequency of demand (or request).

The impatience reaction function f_(i)(V1 _(ri)) depends on user'sbehavior and can be any arbitrary function. As an example, it may be apower function such as f_(i): V1 _(ri)→V1 _(ri) ^(ri), where ri is anyreal number, or a combination of power and root functions such as f_(i):V1 _(ri)→V1 _(ri) ^((ri−1)/ri) where again ri is any real number. Theimpatience reaction function f_(i)(V1 _(ri)) and the parameter ri mayvary with the content item CIi. The identity impatience reactionfunction f_(i): V1 _(ri)→V1 _(ri) is well suited to achieve anallocation of items to cache memory as a function of the square root ofpopularity, which is known to be optimal for minimizing delay. Moregenerally, different impatience reaction function can minimize a givenobjective that represents better user's behavior.

For instance, N is a power function of the type A.f_(i)(V1 ri)=A.V1_(ri) ^(ri), where A is a chosen normalization constant. But, N may bedetermined by means of other impatience reaction functions using V1_(ri) and ri. For instance, such a function may be an exponential.

So, the invention offers a mechanism which makes an average number <Ci>of copies per request for a content item CIi. If newly made replicationsoverwrite replications currently in first cache memory CMj with equalprobability, then in steady-state the proportion of space taken up byeach content item CIi in the distributed first cache memories CMj shouldbe equivalent to the ratio of the number of copies made for that contentitem CIi to the number of copies made for all the content items.Consequently, in steady state each content item CIi should have a numberof copies X; proportional to frequency d_(i) of requests for thatcontent item CIi times the average number of copies <Ci> made for thatcontent item CIi per request:

X _(i) α d _(i) <Ci>=<f(V _(r1i))>.

Ignoring skew, one can claim that <Ci>.≈f(<V_(r1i)>) and that the peermeetings follow a Poisson distribution <Ci>=X/X_(i).

Consequently, when f(.)=(.)^(r−1) one has:

$\left. \left. {X_{i} \propto {{di} \cdot \left( \frac{x}{x_{i}} \right)^{r - 1}}}\Rightarrow{X_{i}^{r} \propto {d_{i} \cdot X^{r - 1}}} \right.\Rightarrow X_{i}\Rightarrow{\propto d_{i}^{\frac{1}{r}}} \right.,$

and when f(.)=(.)^((r−1)/r) one has:

$\left. \left. {X_{i} \propto {{di} \cdot \left( \frac{x}{x_{i}} \right)^{\frac{r - 1}{r}}}}\Rightarrow{X_{i}^{\frac{1}{r}} \propto {d_{i} \cdot X^{\frac{r - 1}{r}}}} \right.\Rightarrow X_{i}\Rightarrow{\propto d_{i}^{r}} \right.$

This is the device D, which is associated to a peer Pj having togenerate a replication for another peer Pj′, that authorizes its peer Pjto proceed to such a generation after having determined if it waspossible.

This is also a device D which determines (or computes) N for itsassociated peer Pj, from the current value V1 _(ri) of the requestcounter RC1 _(ji) (which is associated to a new content item CIireceived by its associated peer Pj) and the impatience reaction functionf_(i) associated to this content item CIi. Such a computation can becarried out by a device D during the first step (i). In this case thedevice D may create not only one set (or mandate) for N replications ofa content item CIi by its associated peer Pj, but N sets (or mandates),one for each of the possible N replications of a content item CIi.

During the second step (ii), each time a peer Pj (for instance P1) meetsanother peer Pj′ which does not yet possess a content item CIi that thispeer P1 stores in its first cache memory CM1 and is still authorized toreplicate, one may generate a replication of this content item CIi bymeans of the associated set of instructions (or mandate). Then the peerP1 transmits this generated replication to the other peer Pj′.

Such a replication may be generated either on request of the other peerPj′, or automatically just because peer P1 has discovered that the otherpeer Pj′ was not storing the content item CIi in its first cache memoryCMj′ and even if the other peer Pj′ has not requested this content itemCIi.

When the other peer Pj′ receives the replication of a content item CIi,it stores it into its first cache memory CMj′. If the latter (CMj′) isfull the other peer Pj′ preferably replaces the oldest content item ofits first cache memory CMj′ with the received replication. Some contentitems CIi may be “sticky”, i.e. cannot be deleted. Such a sticky contentitem can be a content item which is initially provided by the contentserver CS, for instance.

As mentioned before, during the second step (ii), when a peer Pj (forinstance P1) receives a content item CIi, it stores this content itemCIi into its first cache memory CMj. But, one may also create andassociate a replication counter RC2; to this received content item CIi,with an initial value V2 _(ri) equal to N, for the concerned peer Pj.

Since one has V2 _(ri)=A.f(V1 _(ri)) and since f(.) may be a power orany function, V2 _(ri) may sometimes not be an integer. In this lastcase it is important not to do rounding and choose the closest integer.This can be done as follows. When V2 _(ri)>1 one may proceed exactly asmentioned before (replication when possible and then decrement of thereplication counter RC2 _(ji) by 1). When 0<V2 _(ri)<1, which willhappen eventually if V2 _(ri) is not an integer after it has beendecremented by 1 several times, one may take a uniform random variable Uin the interval [0;1] with a random number generator, and if U<V2 _(ri)then one may proceed to a replication or else one does nothing and onesets V2 _(ri) to 0. So, whatever the value of V2 _(ri)=A.f(V1 _(ri))then the expected number of replication is exactly V2 _(ri) (and not aninteger approximation of it). This may be important to avoid bias (andespecially when A is small).

So, each time this peer Pj generates a replication of a content item CIiwhich is associated to a replication counter RC2 _(ji) and which isstored into its first cache memory CMj, one may decrement by one thevalue V2 _(ri) of this replication counter RC2 _(ji), and when thereplication counter value V2 _(ri) becomes equal to 0, one deletes thereplication counter RC2 _(ji). Therefore, peer Pj cannot be authorizedagain to generate a replication of the content item CIi which wasassociated till now to this deleted replication counter RC2 _(ji),except if the peer Pj decides, after some time, to request again thesame content item. This last case may happen in case of returningrequest (or demands), i.e. when a peer wishes to access a given filemultiple times but not necessarily to keep it in memory all the time.

This is a device D which creates and associates a replication counterRC2 _(ji) to a content item CIi received by its associated peer Pj, withan initial value V2 _(ri) equal to the current value V1 _(ri) of therequest counter RC1 _(ji) associated to the considered content item CIi.This is also a device D which will decrement the value V2 _(ri) of areplication counter RC2 _(ji) that it has created and which will deletethis replication counter RC2 _(ji) when its value V2 _(ri) becomes equalto 0.

Preferably, when a content item CIi is no more stored into the firstcache memory CMj of a peer Pj, while the value V2 _(ri) of thereplication counter RC2 _(ji), which was associated to this content itemCIi, is smaller than N, one may keep alive this replication counter RC2_(ji) with its current value V2 _(ri). So, if the considered peer Pjreceives later again a new copy of this content item CIi, one mayassociate the kept alive replication counter RC2 _(ji) with its currentvalue V2 _(ri) to this new copy. This is to avoid that some replicationsget cancelled, which would bias the allocation of content items to cachememory too much in favor of popular items.

This is a device D which keeps alive a replication counter RC2 _(ji) andproceeds to its re-association when necessary.

A replication counter RC2 _(ji) may be kept alive indefinitely till itis deleted because its current value V2 _(ri) became greater than N.But, in a variant, one may keep alive the replication counter RC2 _(ji)with its current value V2 _(ri) during a chosen period of time. In thiscase, if a peer Pj receives a new version of a content item CIi beforethe expiration of the period of time which is associated to thecorresponding replication counter RC2 _(ji), one may associate thisreplication counter RC2 _(ji) with its current value V2 _(ri) to the newversion received. Otherwise this replication counter RC2 _(ji) isdeleted at the expiration of its associated period of time. This is adevice D which manages each period of time associated to eachreplication counter RC2 _(ji) that it keeps alive.

When N is computed (or determined) during the first step (i) and that Nsets (or mandates) are generated (by a device D) for N replications of acontent item CIi by a peer Pj, each time a peer Pj is authorized (by itsdevice D) to generate a replication of a content item CIi, it may use aremaining one of the N sets that have been previously created forgenerating replications of this content item CIi. But such an option isnot mandatory because a peer Pj may also use N times the same set (ormandate), previously created for generating N replications of thiscontent item CIi, as long as the corresponding replication counter RC2_(ji) is not greater than N.

The invention implicitly adapts to the current cache memory allocationand collection of requests. Indeed, computing the optimal allocation ofcontent items to cache memory requires to have a good estimate of thefrequency of demands (or requests) for each content item, and it can becomputationally expensive. This invention avoids this step, by finding adistributed adaptive mechanism which is shown to converge to thisoptimal point, without the need to maintain estimate of frequency ofdemand (or request).

Moreover, the invention does not require to monitor popularity ofcontents. In fact content popularity is implicitly taken into accountthrough the impatience reaction function.

More, the invention allows to operate on top of opportunistic bandwidthwhich is ideally suited to nomadic deployment.

The invention is not limited to the embodiments of method, controldevice and peer (or wireless communication equipment) described above,only as examples, but it encompasses all alternative embodiments whichmay be considered by one skilled in the art within the scope of theclaims hereafter.

What is claimed is:
 1. A method for controlling dissemination of contentin a peer-to-peer mode between mobile peers having wirelesscommunication capacities, wherein, each time a peer receives a contentitem said peer had requested and which is associated to a requestcounter, the method comprising: creating at least one set ofinstructions intended for allowing replication of said content item bysaid peer, and authorizing said peer to generate at most N replicationsof said content item for other peers said peer will meet and which doesnot possess said content item, where N is an integer value depending ona current value V1 _(ri) of said request counter and of a determinedimpatience reaction function f_(i) representative of the mean time saidpeers are ready to wait for obtaining said content item; wherein N is apower function of the type Ax f_(i)(V1 _(ri))=Ax V1 _(ri) ^(ri), where Ais a chosen normalization constant and r_(i) is a real number.
 2. Themethod according to claim 1, wherein in the authorizing step, each timesaid peer is in contact with another peer which does not possess thecontent item that said peer is still authorized to replicate, areplication of said content item is generated by means of the associatedset of instructions, and said peer transmits said generated replicationto said other peer.
 3. The method according to claim 2, wherein saidreplication of said content item is generated only if said other peerhas requested said content item.
 4. The method according to claim 2,wherein said replication of said content item is generated automaticallyfor said other peer even if said other peer has not requested saidcontent item.
 5. The method according to claim 1, wherein each time apeer receives the content item, said peer stores said content item intothe cache memory, and associates a replication counter to said contentitem, with an initial value V2 _(ri) equal to N, for said peer, and eachtime said peer generates a replication of a content item associated to areplication counter and stored into said cache memory, the value V2_(ri) of said replication counter is decremented by one, and when saidreplication counter value V2 _(ri) becomes equal to 0, said replicationcounter is deleted.
 6. The method according to claim 5, wherein when thecontent item is no more stored into a cache memory of a peer, while thevalue V2 _(ri) of the replication counter associated to this contentitem is smaller than N, said replication counter is maintained with itscurrent value V2 _(ri), and if said peer receives again this contentitem, said replication counter with its current value V2 _(ri) isassociated with said received content item.
 7. The method according toclaim 6, wherein said replication counter is maintained with its currentvalue V2 _(ri)-during a chosen period of time, and if said peer receivesagain the content item before the expiration of said period of time,said replication counter with its current value V2 _(ri) is associatedwith said received content item, otherwise said replication counter isdeleted at the expiration of its associated period of time.
 8. Themethod according to claim 1, wherein in the creating step N sets ofinstructions for replications of said content item are created, and eachtime a replication of said content item needs to be generated, one usesa remaining one of said N created sets associated to said content item.9. A method for controlling dissemination of content in a peer-to-peermode between mobile peers having wireless communication capacities,wherein, each time a peer receives a content item said peer hadrequested and which is associated to a request counter, the methodcomprising: creating at least one set of instructions intended forallowing replication of said content item by said peer, and authorizingsaid peer to generate at most N replications of said content item forother peers said peer will meet and which does not possess said contentitem, where N is an integer value depending on a current value V1 _(ri)of said request counter and of a determined impatience reaction functionf_(i) representative of the mean time said peers are ready to wait forobtaining said content item; wherein N is a power function of the typeAx f_(i)(V1 _(ri))=Ax V1 _(ri) ^((ri−1)/ri), where A is a chosennormalization constant and r_(i) is a real number.
 10. The methodaccording to claim 9, wherein in the authorizing step, each time saidpeer is in contact with another peer which does not possess the contentitem that said peer is still authorized to replicate, a replication ofsaid content item is generated by means of the associated set ofinstructions, and said peer transmits said generated replication to saidother peer.
 11. The method according to claim 10, wherein saidreplication of said content item is generated only if said other peerhas requested said content item.
 12. The method according to claim 10,wherein said replication of said content item is generated automaticallyfor said other peer even if said other peer has not requested saidcontent item.
 13. The method according to claim 9, wherein each time apeer receives the content item, said peer stores said content item intothe cache memory, and associates a replication counter to said contentitem, with an initial value V2 _(ri) equal to N, for said peer, and eachtime said peer generates a replication of a content item associated to areplication counter and stored into said cache memory, the value V2_(ri) of said replication counter is decremented by one, and when saidreplication counter value V2 _(ri) becomes equal to 0, said replicationcounter is deleted.
 14. The method according to claim 9, wherein whenthe content item is no more stored into a cache memory of a peer, whilethe value V2 _(ri) of the replication counter associated to this contentitem is smaller than N, said replication counter is maintained with itscurrent value V2 _(ri), and if said peer receives again this contentitem, said replication counter with its current value V2 _(ri) isassociated with said received content item.
 15. The method according toclaim 14, wherein said replication counter is maintained with itscurrent value V2 _(ri)-during a chosen period of time, and if said peerreceives again the content item before the expiration of said period oftime, said replication counter with its current value V2 _(ri) isassociated with said received content item, otherwise said replicationcounter is deleted at the expiration of its associated period of time.16. The method according to claim 9, wherein in the creating step N setsof instructions for replications of said content item are created, andeach time a replication of said content item needs to be generated, oneuses a remaining one of said N created sets associated to said contentitem.